Effects of Face Masks on Respiratory Performance: A Within-Subject Design Study

: There is an ongoing debate about whether wearing a facemask impacts respiratory performance, which is especially crucial in the prevention of COVID-19 transmission. This pre-and post-intervention within-subject design study aimed to quantify the impact of wearing a medical facemask during deep breathing on respiratory functions and compare it to deep breathing without a facemask. A total of 100 samples (n = 100) were obtained from a single healthy young male adult (age = 24 years) who underwent pulmonary function measurement before and after 5 min of deep breathing twice a day (morning and night) for 25 days without a facemask, followed by wearing a 4-ply medical face mask for the following 25 days. Significant improvements in all parameters (mean ± SD), including tidal volume (38.04 ± 46.97 mL, p < 0.005), vital capacity (34.08 ± 105.36 mL, p = 0.027), forced vital capacity (0.11 ± 0.11 L, p < 0.005), forced expiratory volume in 1 s (0.13 ± 0.13 L, p < 0.005), peak expiratory flow (0.36 ± 0.74 L/s, p < 0.005), and forced expiratory flow at 25–75% of forced vital capacity (0.04 ± 0.55 L/s, p < 0.005), were found without the facemask, whereas significant an improvement in forced expiratory volume in 1 s (0.05 ± 0.18 L, p = 0.049), a significant reduction in vital capacity ( − 29.98 ± 103.39 mL, p = 0.046), and no other significant changes were observed with the medical facemask. It was suggested that face masks exert breathing resistance but do not affect deep breathing performance. These results provide further knowledge of the effect of a facemask during deep breathing on respiratory performance.